Apparatus and method for internal repair of conduits

Abstract

An apparatus and method for internal repair of pipes and conduits, such as sewer pipes, pressurized water mains, water wells, and natural gas lines. The conduit repair apparatus includes a sleeve with locking mechanism to lock the sleeve in a tubular configuration. The sleeve is made of metallic or rigid plastic sheet having perforations. Some of the perforations are shaped like elongated slots and strips. A number of resilient O-rings are applied over the outer surface of the sleeve. A resilient membrane is applied over the O-rings. In one embodiment, a reinforcement band is used, and an additional layer of O-rings are included between the membrane and the reinforcement band.

The invention claimed is: 
     
       1. An apparatus for internal repair of pipes and conduits comprising:
 a metal core coiled around a longitudinal axis adapted to be installed within a conduit at a repair site; 
 a sealing structure surrounding said core, said sealing structure designed to prevent conduit-conveyed fluid from escaping from the conduit at the repair site, said sealing structure comprising:
 a plurality of solid resilient O-rings applied over the outer surface of the core; 
 a resilient sealing membrane applied over the O-rings; and 
 a reinforcement band applied over the resilient sealing membrane; 
 
 said metal core being structured and arranged to be moved from a coiled pre-installed configuration to an expanded, coiled, and sealed installed configuration; 
 said core comprising pressure-equalizing open perforations extending through the metal core, said pressure-equalizing open perforations being structured and arranged to equalize internal pressure with an external pressure around said core during both (1) said movement from the pre-installed configuration to the installed configuration, and (2) after said movement, while in the installed configuration; 
 said pressure-equalizing open perforations comprising a plurality of perforations extending along a majority of a circumference of the metal core. 
 
     
     
       2. A repair apparatus according to  claim 1 , wherein:
 said perforations comprise elongated slots, with strips between respective successive slots, to allow shaping of the apparatus by replicating, at the repair site, a shape of an abnormality along a surface of the conduit or at a joint within the conduit. 
 
     
     
       3. A repair apparatus according to  claim 1 , wherein:
 said core comprises a rolled stainless steel sheet. 
 
     
     
       4. A repair apparatus according to  claim 1 , wherein:
 said reinforcement band comprises elongated slots, with strips between respect successive slots, to allow shaping of the apparatus by replicating, at the repair site, a shape of an abnormality along a surface of the conduit or at a joint within the conduit. 
 
     
     
       5. A repair apparatus according to  claim 1 , wherein:
 said sealing structure comprises a reinforcement band applied between the resilient sealing membrane and the O-rings. 
 
     
     
       6. A repair apparatus according to  claim 1 , wherein:
 said sealing structure comprises a curable flexible sealant applied on the sealing membrane. 
 
     
     
       7. A repair apparatus according to  claim 5 , wherein:
 said sealing structure comprises an additional layer of O-rings applied between said reinforcement band and said resilient sealing membrane. 
 
     
     
       8. A repair apparatus according to  claim 1 , wherein:
 said core comprises outward bent circumferential edges to create smooth transition from said conduit diameter to a diameter of the core. 
 
     
     
       9. A repair apparatus according to  claim 1 , wherein:
 said sealing structure comprises said solid resilient O-rings with different body diameters. 
 
     
     
       10. A method of the internal repair of a conduit using the apparatus of  claim 1 , said method comprising:
 (a) applying the resilient sealing membrane around the core and over the O-rings; 
 (b) inserting said repair apparatus, having said metal core, and said sealing structure applied thereto, within the conduit at the site of repair; 
 (c) expanding said repair apparatus to lock said apparatus into a tubular installation configuration and to compress said sealing structure between inner surface of the conduit and said sealing structure; 
 (d) locking said repair apparatus into the tubular configuration at installation pressure, while allowing equalization of pressure internal and external of said core sleeve via the open perforations, and satisfying the following conditions:
 (i) for pressure pipe repair, said O-rings surrounding said core are maintained in a compressed condition even when a service pressure is applied in the conduit, and when conduit diameter is expanded under said pressure; 
 (ii) same as condition (i), except where temperature changes and pressure is constant, or where both pressure and temperature change; 
 (iii) under infiltration pressure, said O-rings are compressed sufficiently to resist said pressure and to prevent gap creation between the repair apparatus and the conduit. 
 
 
     
     
       11. A repair method according to  claim 10 , further comprising:
 before inserting said repair apparatus, applying a resilient curable sealant over the resilient sealing membrane. 
 
     
     
       12. A repair method according to  claim 10 , wherein:
 said pressure-equalizing open perforations extend through the metal core; said pressure-equalizing open perforations comprise a plurality of perforations extending along a majority of a circumference of the metal core. 
 
     
     
       13. A repair method according to  claim 10 , wherein:
 said plurality of perforations are round perforations. 
 
     
     
       14. A repair method according to  claim 10 , wherein:
 said pressure-equalizing open perforations include round perforations and slot-shaped perforations. 
 
     
     
       15. A repair method according to  claim 14 , wherein:
 the slot-shaped perforations form a band of successive slots; 
 said inserting of the repair apparatus comprises inserting the repair apparatus so that the band of successive slots bridge a joint of the conduit. 
 
     
     
       16. A repair method according to  claim 10 , wherein:
 said pressure-equalizing open perforations are unblocked in the installation configuration. 
 
     
     
       17. A repair apparatus according to  claim 1 , wherein:
 said pressure-equalizing open perforations are unblocked in the installed configuration of the metal core. 
 
     
     
       18. A repair apparatus according to  claim 1 , wherein:
 said perforations include round perforations. 
 
     
     
       19. A repair apparatus according to  claim 2 , wherein:
 in addition to said elongated slots, said perforations include round perforations. 
 
     
     
       20. An apparatus for internal repair of conduits for conveying fluids, said apparatus comprising:
 a metal core coiled around a longitudinal axis adapted to be installed within a conduit at a repair site; 
 the metal core being structured and arranged to be moved from a coiled pre-installed configuration to an in-use expanded, sealed, and installed configuration; 
 in the in-use expanded, sealed, and installed configuration, a sealing structure surrounds the core, the sealing structure comprising:
 a plurality of resilient O-rings applied over the outer surface of the metal core; and 
 a resilient sealing membrane applied over the O-rings; 
 
 the metal core comprising open perforations extending through the metal core, the open perforations being structured and arranged to allow fluids, conveyed through the metal core while the metal core is in the in-use expanded, sealed, and installed configuration, to move through the open perforations and to expand the resilient sealing membrane toward the conduit at the repair site; 
 said pressure-equalizing open perforations comprising a plurality of perforations extending along a majority of a circumference of the metal core. 
 
     
     
       21. An apparatus for internal repair of fluid-carrying pipes and conduits, said apparatus comprising:
 a metal core coiled around a longitudinal axis adapted to be installed within a conduit at a repair site; 
 a sealing structure surrounding said core, said sealing structure further comprising:
 a plurality of solid resilient O-rings applied over the outer surface of said core; and 
 a resilient sealing membrane applied over the O-rings; and 
 a reinforcement band applied over the resilient sealing membrane and the O-rings; 
 
 said metal core being structured and arranged to be moved from a coiled pre-installed configuration to an expanded and installed configuration; 
 said core comprising pressure-equalizing open perforations extending through the metal core designed to allow fluid carried by the conduit to flow through said perforations in said installed configuration and apply fluid operating pressure against the resilient sealing membrane in a direction against the conduit, said pressure-equalizing open perforations equalizing fluid operating pressure within the metal core with the fluid operating pressure outside of the metal core; 
 said pressure-equalizing open perforations comprising a plurality of perforations extending along a majority of a circumference of the metal core; 
 the metal core further comprising a self-actuable locking assembly to lock respective edge regions of the core in the installed configuration; and 
 the O-rings are positioned to apply an external loading to the core, thereby retaining the core locked in the installed configuration. 
 
     
     
       22. A repair apparatus according to  claim 1 , wherein:
 the repair apparatus comprises means for preventing water from passing from the core through the sealing structure to the conduit at the repair site. 
 
     
     
       23. A repair apparatus according to  claim 22 , wherein:
 said means comprises a resilient sealing membrane surrounding the core. 
 
     
     
       24. A repair apparatus according to  claim 23 , wherein:
 the resilient sealing membrane is made of rubber. 
 
     
     
       25. A repair apparatus according to  claim 1 , wherein:
 the sealing structure does not include a curable sealant. 
 
     
     
       26. A repair apparatus according to  claim 1 , wherein:
 the resilient sealing membrane has protruding undulations along a length of the core creating by the O-rings being spaced along the length of the core. 
 
     
     
       27. A repair method according to  claim 11 , wherein:
 said resilient curable sealant comprises a sealant that is resilient and elastic after curing. 
 
     
     
       28. A repair method according to  claim 10 , wherein:
 no resilient curable sealant is applied over the resilient sealing membrane.